Blender freezes / hangs when importing FBX exported from Rokoko Studio
This is caused by the way Blender imports FBX animations. It's extremely unoptimized which can cause long and complex animations (like motion capture ones) to take hours to import. You should use the BVH format with the HumanIK skeleton in the exporter options of Rokoko Studio to export your animation. This format can be imported into Blender quickly without any issues.